Ugh, my brain hurts...
Ok guys, here's a real scientist's assessment of this grand discovery:
1) It's bad science. It's not not-scientific, it's just bad. Cargo cult science, really...
2) Yes, the result is mindblowingly obvious. While it's nice to see an obvious hypothesis as "full plate armor restricts movement" being put to the test Mythbusters style (coming up next week: "swimming in a lake will make your hair wet"), the result is of little use. Yes, wearing heavy things restricts movement, obvious. The exact mechanisms by which this happens are interesting, such as the breastplate restricting breathing, but also not exactly a great discovery.
3) The conclusion is...argh. You generally want to have some sort of predictive or applicative use of your result in there. What does it mean? What future work could be done? How is this useful to industry X who funded your work? Well, there's nothing you can actually say about "plate armor restricts movement."
4) The sample size is quite small. While that's not a huge problem given the nature of the experiment, it's not exactly good science either. When it comes to sample size, you want as many as your budget allows.
5) A much more interesting experiment would be whether the time required to complete a mixed terrain run, as well as average heartbeat and required oxygen decrease over time (that would be several months) as the subjects are trained by an expert in the proper use of the armor. At least this would tell us whether some of the medieval tales of knight fightin' are actually feasible, given that they had to have trained extensively.